In this study, the total phenol content and antioxidative activity of fractions from Hemerocallis fulva leaves were evaluated in terms of reducing power, superoxide dismutase (SOD)-like activity, the inhibitory effect on linoleic acid autoxidation and metal-ion (Cu^2＋) chelating effect. Among five fractions, the ethyl acetate fraction showed the highest total polyphenol content (749 mg Chl/g), and also exhibited an excellent reducing power (1.16∼3.35 at 100∼500 Ռg/ml). SOD-like activities of the chloroform-and ethyl acetate-fractions at the concentration of 100 Ռg/ml showed 33.3% and 22.3%, respectively. In addition, the chloroform fraction showed the highest inhibitory effects (77.5∼90.2% at 25∼100 Ռg/ml) on linoleic acid autoxidation system. Metal-ion (10^－4 M CuSO₄) chelating effect of the butanol-and ethyl acetate-fractions at the concentration of 100 Ռg/ml showed 30.2% and 36.7%, respectively. Among the fractions, the ethyl acetate fraction exerted the highest total phenol content and the strongest antioxidative activity. These results indicate that H. fulva may be useful as potential antioxidant sources for improving human antioxidant defense system. (Cancer Prev Res 17, 18-263, 2012)

Keywords: Hemerocallis fulva, Total phenol content, Reducing power, SOD-like activity, Linoleic acid autoxidation